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Table of Contents
Problem Scenario
Everyone knows how onions affect your eyes, how just by cutting into one will make your eyes sting and water. Could there be some way ofBroad Question
What temperature onion hurts your eyes the least?Specific Question
Does the temperature of an onion affect the gas pressure of the onion resulting in less tears when it is cut open?Hypothesis
It is hypothesized that chilling an onion before it is cut will reduce that rate of tears.Graph of Hypothesis
Variables
Independent Variable:
The temperature of the onion.Dependent Variable:
Gas pressure (how it affected your eyes)Variables That Need To Be Controlled
Type of OnionVocabulary List That Needs Explanation
sulfuric acid: a clear, colorless to brownish, dense, oily, corrosive, water-miscible liquid, H2 SO4, usually produced from sulfur dioxide: used chiefly in the manufacture of fertilizers, chemicals, explosives, and dyestuffs and in petroleum refining.General Plan
My general plan is to set the onions to the temperatures, cut, record the data, and make into graphs.Potential Problems and Solutions
Onions set at a certain temperatureSafety Or Environmental Concerns
knife may be sharponions may irritate eyes
Experimental Design
Controlled, manipulated experiment
Number of Trials:
I will conduct three trials.Number of Subjects in Each Trial:
1 subject.When data will be collected:
It will be collected during class where the gas pressure sensor will collect data for approximately 15 minutes per trial.Number of Observations:
I will observe it three times.Where will data be collected?:
I will collect my data in the science class room using a gas pressure sensor.Resource and Budget Table
Time Line
Background Research
Everyone knows how cutting an onion makes your eyes water. But could there be a way to manipulate an onion to control this annoying variable? If so, how? From researching this topic I have found that many people have attempted to use temperature as a way to reduce the affect the onion has on their eyes. to see if this idea was in any way reasonable, I first had to learn a little more about what I was working with; the onion.From what I have found, it seems as if the reason for the stinging eyes is all chemical, set off in a chain reaction. When you cut into an onion, you are breaking cells, therefor releasing the contents. Amino acid sulfoxides form sulfenic acids, and mix with enzymes that were kept separate, producing propanethiol S-oxide. This chemical wafts up towards your eyes and, mixing with your eyes natural moisture, produces sulfuric acid. The eyes, now burning from the acid, automatically produce more tears to wash it out.
After the initial research I concluded that this method of reducing the mixing of chemicals within an onion may be worth a shot. To decide exactly how I would conduct my experiment, I read over some articles about how some other people had done theirs. Many, using the idea that temperature would affect chemical mixing, tried cooling the onion. Some even said that cutting the onion under a steady stream of flowing water helps. I decided to go with the temperature theory, setting three different onions to room temperature (about 65 degrees), and about 40 degrees, and 20 degrees (cold and freezing).
Temperature seems to be an affective way of controlling the onion's chemical reactions. I plan to test this theory for myself, especially focusing on different, colder temperatures of onions.
References
"Why Do Onions Make You Cry?" About.com Chemistry. Web. 02 May 2012. <http://chemistry.about.com/od/chemistryfaqs/f/onionscry.htm>.
Detailed Procedure
Materials
3 onionsknife
cutting board
airtight container
gas pressure sensor
Set Up
place 1st onion in enclosed space, room temperatureplace 2nd onion in the refrigerator, cold onion
place 3rd onion in freezer, freezing onion
allow 24 hours for onion to reach set temp.
Conducting Experiment
using knife and cutting board, cut a 2cm thick piece of onion lay onion slice flat and cut in half, and then in half againplace onion pieces into airtight container and seal
record data using gas pressure sensor (repeat for 2nd and 3rd onion, cold and freezing.)
Diagram
Photo List
Results
All Raw Data
Graphs
Photos
Data Analysis
From what I have seen on my graphs, the frozen onion omits much less gas, resulting in a lower gas pressure overall. The room temperature onion and the cold onion had a higher overall gas pressure, but the two were almost identical in pressure.Conclusion
From my experiment I can conclude that a frozen or cold onion will release less gas than regular or room temperature onion, therefore hurting your eyes the least when cut open. The cold onion's gas pressure was less than the normal one's, but the frozen onion's had a more dramatic decrease in pressure. If you need to cut an onion any time soon I would suggest freezing in first or if that is not possible, chilling it a little.Discussion.
The relationship between my variables is strong because when I changed the independent variable the dependant variable changed accordingly. I was able to answer my question with enough information to back up my conclusion. My data will help people in the kitchen. Instead of storing onions at room temperature as usual, store them in the fridge or freezer for an easier kitchen experience.Benefit to Community and/or Science
Abstract
Does the temperature of an onion affect the rate at which it makes you cry? It is hypothesized that chilling an onion before it is cut will reduce the rate of tears. Cutting an onion arouses a gas contained within the onion to emit a passive sulfur compound. When this upwardly mobile gas encounters the water produced by the tear duct in our eyelids, it produces sulfuric acid. In response to the acid our eyes automatically blink and produce tears which wash out the sulfuric acid. After conducting my experiment I collected the data and graphed it. The cold onion and the room temperature onion had the exact same gas pressure, but the frozen onion's was much lower. This means that an onion that is frozen will, when cut open, produce less sulfuric acid, therefore hurting your eyes the least.